We request funds for the purchase of a Leica EM UC7 ultramicrotome for sectioning biological and biomaterials samples at room temperatures. The new instrument will help provide for the ultramicrotomy needs of over 60 user laboratories at the University of Massachusetts Medical School (UMMS) and the Graduate School of Biomedical Sciences (GSBS). The new ultramicrotome will be housed in the Core Electron Microscopy Facility of the Medical School, and will replace a 30-year old Reichert-Jung Ultracut E, that while still functioning, is now considered obsolete, has become unreliable, and is no longer supported by the manufacturer (parts or service). Ultramicrotomes are used to cut thin sections of cells and tissues that are required for understanding their detailed structure and the changes in structure that underlie human disease. Many tissue-engineering strategies involve the delivery of cells via porous polymer scaffolds. Obtaining sections of the emerging tissue is necessary to analyze the characteristics of the microscopic environment. The Core Electron Microscopy facility supports projects ranging from studies of the structure of muscle, microtubule formation and stabilization, stem cell and germ cell differentiation, cilia and flagell structure, just to mention a few. All are important topics in the understanding of the normal function and structure of the human body and all require ultramicrotomy. The Leica EM UC7 Ultra-microtome offers a range of outstanding features and benefits over our old Reichert-Jung Ultracut E model. Each user, from absolute beginner students to our most skilled ultra- microtomist will benefit from this modern instrument. The eucentric movement of the viewing system allows examination of sections even with lowered water level (as with Lowycryl, and LR White resins, used in immune-labeling projects). The touch sensitive control unit of the Leica EM UC7 enables fast and safe alignment of knife and specimen with help files and prompts, simplifying the trimming- process while preparing samples for sectioning. Funding this grant will help us provide state-of-the-art instrumentation for our shared research Electron Microscopy Core Facility, utilized by over 100 individual researchers and their graduate students as well as the faculty and graduate students at several colleges in the surrounding area. The new instrument will greatly enhance the ability of our investigators and students to carry out their microtomy-related studies, it will greatly improve the quality and speed of data collection, and it will make possible types of observations that are impossible with our older (obsolete) instrument.